I've owned the M&P 9 compact, 4516, Model 52 and currently have a nice 659. By far, I prefer the 659. Its rugged good looks (heck it should have gotten star billing in the movie Reservoir Dogs), reliability, heft and low recoil make it an excellent gun for home defense, plinking and winter carry. I have 3 off-the-shelf holsters made for my SIG P-226 and the Model 659 fits perfectly in them.

I paid $350 for the 659 a few months ago at a local pawnshop, so the 2nd Gen Smiths can still be found at reasonable pricing. I'm a "horse trader" by nature, but my 659 is a keeper.